A Listserv is a method of communicating with a group of people via email. You send one email message to the “reflector” email address, and the software sends the email to all of the group’s subscribers.
People join because they share a common interest. That shared interest might be a hobby, recreational pursuit, educational, work related, health related, or members of a family keeping in touch.
People can get on and off (subject to the list owner’s approval) by themselves. There are separate email addresses for these administrative functions.
There are millions of listserves, or electronic mailing lists on the Internet. Some are free like Yahoo Groups and Google Groups. These groups are supported by ads that can appear in each email message. And by selling the demographic and behavioral attributes of your list members to advertisers.
Other listserve hosting companies charge money to pay for the software, computers and bandwidth. Typically the list owner or organization pays the fee, and allows subscribers to join for free.
The common thread is the listserv software that manages the subscriptions, handles bounces, and gets the email message out to small groups of 10 people up to very large groups of hundreds of thousands of people.
There are many different brands of software for this purpose, including Listserv itself, Majordomo, Smartlist, GNU Mailman, Sympa and . These software packages provide the ability to subscribe, unsubscribe, go on vacation, process bounces, and send messages to the lists.
And there are many different words used to describe a listserve, including mail groups, email discussion groups, online discussion group, electronic mailing list, discussion board or message board.
Yet they all allow people to bypass time and space, and communicate with like minded people from the comfort of their email inbox.